I am developing an app using EWS and the requirement is to categorize whether it is a new mail or reply to existing one. It was pretty easy in outlook as we have conversation index and the length of it tells you that. I am struggling with EWS conversation index property in message as i honestly don't know how to read it or combine it. I can't use subject line prefix as it is not right approach i believe. can someone please help?
Gaurav